The invention concerns a device for forming at least one groove in a friction layer of a covered plate for a force transmission aggregate, in particular for a clutch disk, as well as a process for forming at least one groove in a friction layer of a friction plate for a force transmission aggregate, in particular for a clutch disk.
Disk clutches generally include a plurality of disks, which can be produced using the device described below or, as the 1 case may be, using the process described below. Conventionally a first group of disks of this type is provided upon a disk carrier fixed against rotation and sliding, and a second group is provided drivable upon a drive hub. The disks of the two groups intermesh or interdigitate in each other in the manner of gear teeth. The two groups are slideable relative to each other in the axial direction and thereby can be brought pair-wise into or out of engagement. A disk clutch of the above-described type is described, for example, in DE 199 06 980 A1.
The individual disks are preferably formed ring-shaped. Distinctions are made between so-called covered disks and so-called steel disks. Covered disks are in general constructed in sandwich-like manner. The base element for a ring-shaped covered disk of this type is a ring carrier, which is comprised for example of steel and is produced preferably by stamping. This sheet metal carrier carries a friction layer on one or both of its ring surfaces. This layer is comprised in general of a fibrous material, such as paper, or is produced from a paper-like material.
There are however also disk clutches or disk brakes, in which the disk is continuous, that is, is produced as a unitary piece of a friction material.
In the above-mentioned force transmission aggregate, the lubrication and cooling of the individual construction components plays an essential role. For this reason a lubricant, preferably oil, is provided between the individual disks. In order to hold the lubricating oil for a predetermined period on the friction surfaces of the disks or, as the case may be, to be able to release oil, the above-mentioned layer exhibits a sponge-like structure. In the non-pressured condition, that is, when there is no contact between adjacent disks, a certain amount of oil storage is taking place, which is again given off or released during actuation and the compression occurring in conjunction therewith. Since the sponge-like structure of the friction layer is however not adequate by itself to ensure that the functional requirements of the force transmission aggregate will be satisfied, it is within the state of the art to introduce grooves into the friction layer of the disk. Depending upon the intended employment of the respective force transmission aggregates, the grooves can be designed or formed in the most diverse design and manner. Depending upon the function to be fulfilled, these grooves can be in the form of rays, lines, curves, criss-cross and the like. Further, the most diverse groove cross-sectional shapes and sizes can be utilized.
According to the state of the art, processes are employed for producing among other things of the above-described grooves, in which the friction layer is removed to define the groove contour.
A material removing process step of this type has been found to be disadvantageous in many respects. In particular, it is not possible, in accordance with this process to apply the friction layer upon the carrier material and to introduce the grooves in a single process step. A continuous manufacturing process is thus not possible. Besides this, this type of material removing process exhibits the disadvantage, that the removed material disperses and soils the disk pre-form or the machine or machine parts.
From the state of the art it is further known to introduce the grooves by a press or stamping process. This is however associated with the disadvantage that the necessary groove depth cannot be achieved, or can be achieved only with great difficulty.
The invention is thus concerned with the task of providing a device or, as the case may be, a process for introduction of grooves into a friction layer of a covered disk, with which, or as the case may be, in which the above described problems no longer occur. In particular, a continuous manufacturing process should be made possible with high speed. The transfer as well as the manipulation of work pieces should occur in simple manner, and contamination should be substantially eliminated. Beyond this, in accordance with the device or, as the case may be, the process, in particular on the basis of the elimination of the above mentioned disadvantages, a cost reduction is achieved.
The task is inventively solved by a device or, as the case may be, a process for introduction of at least one groove in a friction layer of a friction disk or a force transmission aggregate, in particular for a disk clutch, with the features of the characterizing portion of the claims.
Advantageous embodiments and further developments of the invention are set forth in the dependent claims.
The inventive process is based on the idea, that the at least one groove is introduced by a rolling or turning process. Accordingly, the device includes a rolling device with at least one rolling arm for rolling the at least one groove.
During the rolling process the disk is moved under the corresponding rolling device or the rolling device is moved over the disk.
A process of this type can be integrated in simple manner into a continuous manufacturing process. The invention in particular envisions that the one or more grooves are introduced immediately subsequent to the process of gluing or lamination of the friction layer to the carrier material. It has been found that the introduction of the groove via the rolling process is to be carried out at elevated temperature, in order to produce high value grooves. Since the process of gluing the friction layer to the carrier material usually occurs at elevated temperature, the above described rolling process is preferably incorporated into the existing production process. It has further been found that a process of this type is suitable both for the introduction of grooves into a disk provided on one side with a friction layer, as well as for introduction into disks provided on both sides with a frictional layer.
In the following a description will be provided as to the mode and manner in which the inventive device can be constructed in advantageous manner. A first particularly advantageous embodiment of the invention envisions that the rolling device includes a drive shaft rotatable about a rotation axis, co-axially upon which is provided at least one essentially circular shaped template disk, the disk defined by an outer diameter and an outer circumference or outer contour. The at least one rolling arm is thus formed by the outer circumference of the at least one circular shaped template disk. For almost any conceivable groove design to be introduced into a disk, there can be produced in this manner in the shortest possible time a device for introduction of the groove in the friction layer, in which simply one or more template disks are appropriately provided upon the drive shaft. A set of disks of this type is easy to change out.
In order to be able to introduce grooves in various separations in the friction layer of the respective covered disks, it is envisioned in accordance with the invention, that template disks provided side-by-side or adjacent to each other are spaced apart with the aid of appropriate spacer rings of, in certain cases, varying thicknesses. A device of this type is simple in design and manufacture, and therewith is economical. Further, the template disks as well as the spacer rings are easily manufactured and therewith also economical.
As has already been described in detail, depending upon the intended use it may be necessary to introduce the grooves into the friction layer with varying groove depths. This also is easily accomplished in the present described rolling device using one or more template disk set spaced apart by spacer rings in simple manner. Essentially, template disks with (in certain cases, small amount) varying diameters are seated upon the drive shaft.
With the aid of a device described herein comprising template disks and spacer rings, it is possible to introduce grooves in a friction layer, which preferably extend essentially linearly. The manufacture of curved grooves is only possible to a limited extent when using this device, since the circumference of the template disks must exhibit a corresponding curvature. However, in accordance with one variant of the presently described embodiment, groove designs can be produced in simple manner with crisscrossing grooves formed of essentially linearly groove tracks, in which the respective disk passes multiple times through the rolling process, however relative to the preceding process step is rotated by a certain angular amount with respect to the rolling device.
Almost any conceivable groove pattern or design can be achieved with a rolling device of the following described embodiment: In this embodiment the rolling device includes a drum rotatable about a rotation axis with an outer circumference surface, upon which again one rolling flange or multiple rolling flanges are provided. Since a drum of this type, in contrast to the above-described rolling disk, extends in the axial direction, rolling flanges can be provided and arranged in any type and manner. In particular, rolling flanges are possible which extend only partially in the axial direction, or which extend in any other mode and manner, even extending slanted or even curved.
In the simplest case, the outer circumference surface is formed as a cylinder. The introduction of the grooves corresponds then substantially to the above described embodiment. It is however essentially also possible, that the outer circumference surface is formed by the side surfaces of a cylinder with a multi-sided base shape.
It is further envisioned in accordance with the invention that the corresponding rolling flange cross-sections are of various design. In particular, the corresponding cross sections can be of semicircular design, triangular design, trapezoidal design or a right-angled design, depending upon the cross-section of the groove to be produced. It is readily apparent that the cross sectional shape of the rolling flanges in both of the above described rolling devices can be varied.
As already described in detail in the preceding sections, it is advantageous to form the grooves in the friction layer at elevated temperatures. For this reason the invention envisions the provision of a heating device for heating the rolling flanges.
It has further been found to be advantageous to provide a cleaning device for cleaning the rolling device and/or the rolling flanges, even though the presently described inventive process is not a material removing process.
Four illustrative embodiments are shown in the figures and are described in greater detail in the following.